Photosensitive and thermosensitive element,composition and process

ABSTRACT

AMIDOXIMES ARE ACTIVE DEVELOPING AGENTS FOR PHOTOGRAPHIC SILVER SALTS IN STRONGLY ALKALINE SOLUTIONS. THEY MAY BE INCORPORATED IN SILVER HALIDE EMULSIONS AND THEY CAN BE ACTIVATED BY IMMERSION IN ALKALI OR BY APPLICATION OF HEAT. THEY MAY BE USED IN CHEMICAL OR PHYSICAL DEVELOPMENT: SUCH AS, DIFFUSON TRANSFER PROCESSING.

United States Patent 3,794,488 PHOTOSENSITIVE AND THERMOSENSITIVE ELEMENT, COMPOSITION AND PROCESS Richard W. Henn, Pittsford, Burton D. Wilson, Webster, and Paul E. Woodgate, Chili Center, N.Y., assignors to Eastman Kodak Company, Rochester, N.Y. No Drawing. Filed June 14, 1972, Ser. No. 262,905

Int. Cl. G03c 1/06, 5/30 U.S. C]. 96-50 R 12 Claims ABSTRACT OF THE DISCLOSURE.

Amidoximes are active developing agents for photographic silver salts in strongly alkaline solutions. They may be incorporated in silver halide emulsions and they can be activated by immersion in alkali or by application of heat. They may be used in chemical or physical development; such as, diffusion transfer processing.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to certain amidoxime photographic silver salt developing agents and to photographic elements, processing compositions, and to processes employing developer compositions containing certain amidoxime silver halide developing agents. In another of its aspects, it relates to a method of developing a latent image in a photographic element employing the described amidoxime silver halide developing agents.

Description of the prior art It is well known to develop a latent image in a photographic silver halide element using a silver halide developing agent. Developing agents for this purpose have included for example, aminophenol developing agents and polyhydroxybenzene developing agents. This is described, for example, in The Theory of the Photographic Process by Mees and James, 3rd ed., 1966, pp. 278-311.

It has been desirable to provide developing agents which are sufficiently active to provide desired sensitometric properties within the shortest development time and also result in colorless or low-colored oxidation products. Developing agents which provide colorless or low-colored oxidation products are especially desirable in photographic systems in which the oxidation products are not to be removed from the system, such as in systems in which usual washing with water is avoided.

It is, furthermore, desirable 'to find developing agents that can advantageously be employed in a variety of photographic products, for example, in photographic developer and processing solutions, as incorporated developing agents in photographic emulsions, in photographic products that may be processed according to the so-called dry processing techniques, in photographic diffusion transfer products, etc.

Developing agents having such universal applications are unusual. A developing agent, for example, which is desirably employed in a developing solution can be useless as an incorporated developing agent, i.e., the developing agent may not be stable in the emulsion. A developing agent, as incorporated, may cause spontaneous reduction (fogging) or may be lost by oxidation. A developing agent which is incorporated in a photographic element adapted for wet processing may not be desirable for incorporation in a photographic element adapted for dry processing" since most developing agents have a tendency toinduce staining unless washed out from the elements upon processing.

There is a continuing need for compounds which can developnot only exposed photographic silverhalide, but

3,794,488 Patented Feb. 26, 1974 SUMMARY OF THE INVENTION It has been unexpectedly discovered that the amidoximes can be employed as effective developing agents in a wide variety of photographic materials, as described herein. In accordance with the invention, photographic silver salt developing compositions are provided which employ amidoximes having the general formula:

where R may be H, alkyl having 1-12 carbon atoms, aryl having 6 to-12 carbon atoms or heterocyclic having 6 to 12 carbon atoms.

The activity of such developing agent in many photo graphic products is unexpected and unobvious since the oximes are not active silver halide developing agents.

An object of this invention is to provide active developing agents. A further object is ot provide developing agents having low-colored oxidation products. A further object is to provide developing agents which can be incorporated in a photographic emulsion without undesirable oxidation of the agents or fogging of the emulsion. A further objectis to produce photographic emulsions which may be processed by the application of heat.

Another object of this invention is to provide photographic silver salt developing agents capable of providingincreased speeds and strong image discrimination.

A- further object of this invention is to provide photographic silver salt processing composition which provide desired sensitometric properties and developing action wtihout objectionable stain.-

DESCRIPTION O THE PREFERRED EMBODIMENTS The amidoximes particularly useful in the invention have the general structural formula:

wherein Ris an alkyl group, including substituted alkyl groups having 12 carbon atoms, such as methyl, ethyl, propyl, butyl, alicyclic substituted alkyl such as cyclopentylethyl, hydroxyalkyl such ashydroxyethyl, hydroxypropyl, tris(hydroxymethyl)butyl, carboxyalkyl such as carboxymethyl,.carboxyethyl, carboxyphenyl, unsaturated hydrocarbons, including substituted unsaturated hydrocarbons such as vinyl allyl, phenylallyl, alicyclic such as cyclophentyl, methylcyclopentyl, cyclohexyl, cyclohexylbromide, cyclohexenyl, and the like; an aryl group including substituted aryl groups, and having 6 to 12 carbon atoms, as exemplified 'by phenyl, naphthyl, alkaryl, such as xylyl, mesityl, ethylphenyl, propylphenyl, halide substituted phenyl such .as bromophenyl, dichlorophenyl, carboxyphenyl and the like; and a heterocyclic group having 5 or 6 atoms, e.g. 2-furyl, thienyl, benzothienyl,

pyridyl, quinolyl, and the like. In a preferred aspect of this invention, R represents the atoms necessary to complete a 5 or 6 member heterocyclic ring, preferably containing one 'hetero atom such as N or S, the selection of the amidoxime being within the skill of the practitioner in the art.

Illustrative, examples of amidoximes which may be employed according to the invention are:

p-tolyl amidoxime p-bromophenyl amidoxime p-xylyl amidoxime m-carboxyphenyl amidoxime Z-thienyl amidoxime methyl amidoxime 3,4-dichlorophenyl amidoxime 2,5-dichlorophenyl amidoxime p-methoxyphenyl arnidoxime p-chlorophenyl amidoxime.

A significant feature and advantage of the amidoxime developing agents is its substantially low propensity for staining, hence the developing agents need not be washed from the emulsion following processing. This feature is particularly advantageous in rapid machine processing and in photographic elements adapted for dry processing. A second significant feature and advantage is the increase in developing rate obtained when the amidoximes are employed in combination with pyrazolidone silver halide developing agents. This aspect of the invention is illustrated by Example 3 which follows.

When used in such combination, the mole ratio of amidoxime to pyrazolidone developing agent may vary over a wide range. The selection of the ratio is within the skill of the practitioner in the art. The selection of ratios can depend on a number of factors such as the type of photographic system being developed, the method of development, whether the developer combination is incorporated or part of a developer or processing solution or package. A useful mole ratio of amidoxime to pyrazolidone developing agent is 100:1 to about 0.5 :1. A preferred ratio is 20:1 to 5:1. A particularly useful ratio is :1 on a molar basis.

Another significant feature of the developing agents of the present invention is their substantial stability when incorporated in a photographic element. They neither cause nor induce spontaneous reduction, nor are the developing agents lost by oxidation; hence the shelf life of a photographic product is substantially extended.

The developing agents of this invention can be suitably utilized in any of a variety of locations with respect to a photographic system. They can be employed in photographic processing and/or developing solutions, for example, in an aqueous alkaline developer composition. They can be incorporated into a layer of a photographic element such as a silver halide emulsion layer, an overcoat layer or an interlayer of a photographic element. They can be utilized in a developer composition intended for use in a diffusion transfer process or they can be utilized in one or more layers of a photographic element employed in a diffusion transfer process.

Diffusion transfer processes and photographic elements in which the developing agents are useful are described, for example, in US. Pats. 2,352,014 of Rott issued June 20, 1944; 2,543,181 of Land issued Feb. 27, 1951; and 3,337,342 of Green issued Aug. 22, 1967. The developing agents of this invention can also be employed in socalled high-speed difiusion transfer processes as described, for example, in US. Pat. 3,326,683 of Land et al. issued June 20, 1967; or in other types of diffusion transfer processes such as those described in US. Pats. 2,857,274 of Land at al. issued Oct. 21, 1958; 3,020,155 of Yackel et 211, issued Feb. 6, 1962; 2,584,030 of Land issued Jan. 29, 1952; and 2,923,623 of Land issued Feb. .2, 1960. These patents describe typical photographic products suitable for diifusion transfer systems comprising a combination of (a) a photosensitive element which comprises a support having thereon at least one photosensitive silver salt emulsion layer (b) an image-receiving layer, and (c) a rupturable container containing an alkaline processing composition comprising a silver halide developing agent, and typically a silver halide solvent.

The amidoximes can be located in the photosensitive emulsion layer or in contiguous layers of a photographic element and a pyrazolidone developing agent located in the activator solution or layer. The latter arrangement is especially desirable since it allows for the most optimum keeping conditions. Hence in a preferred embodiment there is provided a photographic element comprising a support having thereon at least one photographic silver salt emulsion layer containing an amidoxime described herein; and an activator layer or solution containing 1-phenyl-3-pyrazolidone. The developing agents of this invention can 'be utilized in combination with photosensitive elements which are adapted for processing by the socalled dry photography (heat) development methods. No liquids, vapor or other processing aids need be employed in order to obtain a high image density or desirable image tone in the photosensitive element having incorporated therein the developers of this invention. Dry photography processes are described, for example, in US. Pats. 3,457,075 of Morgan et al. issued July 22, 1969; 3,152,903 of Sheppard et al. issued Oct. 13, 196 or 3,152,904 of Sorensen et al. issued Oct. 13, 1964.

Photographic silver halide emulsion, preparations, addenda, processing and systems can be used as disclosed in Product Licensing Index, vol. 92, December 1971, publication 9232, pp. 107l10, paragraphs I-XI, XIII and XXIV.

Suitable silver halide developing agents which can be employed with the developing agents of the invention include, for example, polyhydroxybenzenes, such as hydroquinone developing agents, e.g., hydroquinone; alkyl substituted hydroquinones such as t-butylhydroquinone, methylhydroquinone and 2,5-dimethyl hydroquinone; catechols and pyrogallol; halogen substituted hydroquinones such as chlorohydroquinone or dichlorohydroquinone; alkoxy substituted hydroquinones such as methoxy hydroquinone or ethoxyhydroquinone; aminophenol developing agents, such as 2,4-diaminophenols, e.g., 2,4- diamino-6-methylphenol, and methylaminophenols; hydroxylamines such as N,N-di(2-ethoxyethyl)hydroxyamine; 3-pyrazolidone developing agents such as l-phenyl- 3-pyrazolidone, including those described in British -Pat. 930,572; an acyl derivative of p-aminophenol such as described in British Pat. 1,045,303; ascorbic acid; hydroxytetronic acid and hydroxytetronimide developing agents; reductone developing agents such as anhydrodihydropyrrolidino hexose reductone and the like.

The photographic developer compositions can include ingredients commonly employed for processing photo graphic elements in addition to the developing agents, e.g., stabilizer compositions, activator compositions, hardener compositions and the like.

The photographic developer compositions according to the invention can contain a silver halide solvent. A variety of silver halide solvents are suitable, such as alkali metal and ammonium thiocyanates, e.g., sodium and potassium thiocyanate and ammonium thiocyanate, alkali metal thiosulfates, such as sodium thiosulfate and potassium thiosulfate, thiourea compounds, and the like.

Any alkaline developer activator can be employed to activate the developing agents of the invention in nondry processing photographic processes so long as the activators provide the desired pH. These include those commonly employed in the photographic are as development activators, such as inorganic alkali, e.g., alkali metal hydroxide including sodium hydroxide, potassium hydroxide and lithium hydroxide, alkali metal carbonate, such as sodium carbonate, sodium bicarbonate, fuming ammonia, and the like as well as organic alkali such as organic amines and aminoalkanols, e.g., ethanol amines and aminodiethanolamine or morpholine. The concentration of development activator can vary depending on the various components of the system, the photographic emulsion... employed, the desired image, and vthe like. .A concentration is usually employed which provides a pH of atrl astab utfi .t gi ally m, a out qt a ut 14. and preferably" about 12 to about 14.

In another embodiment of the invention photosensitiveelements-are provided, said elements comprising a support, at least one silver salt layer and incorporated in said element, a photographic silver salt developing agent of this invention. The developer can be employed in a photographic silver salt emulsion layer, an overcoat layer, a layer under the emulsion layer, or virtually any of the layers contiguous to the silver salt to be developed.

The developing agents of the invention can be employed in photographic elements designed for processingin stabilization type processing. For example, they can be incorporated in one or more layers of aphotographic element which is exposed, activated by contact with alkaline activator, and then contacted 'with a thiocyanate or thjosulfate solution, such as an ammonium thiocyanate, or they 'can be incorporated in the alkaline activator. Such processes are described, for example, in U.S. Pat. 3,326,- 864 of Nishio issuedlune 20, 1967; British Pat. 1,004,302; French Pat. 1,516,556 of Fassbender; and in an article by H. D. Russell, E. C. Yackel and E. G. Grouse in the PSA Journal, Aug'us t 1950, pp. 59-62, entitled Stabili zation Processing of Films and Papers.

The developing agents of this invention as described herein can be used in layers of photographic elements or processing solutions intended for .use in monobath processing such as described in U.S. Pat. 2,875,048 ofHaist et al. issued Feb. 24, 1959, and British Pat. 1,063,844 of Beavers et al., issued Mar. 30, 1967, and in web-type processing, such as described in-U.S-. Pat. 3,179,517 ofTregil lus et al. issued Apr. 20, 1965.

The developing agents of this invention can be emgaloye'gl' in a photographic silver salt emulsion designed for diffusion transfer processing and/or in a developer compositiondesigned f ,developingand stabilizing the element. A typical developer composition is disclosed in U.S. Pat. 3,120,795 of Land et 211. issued Feb. 11, 1964.

Hence, in accordance with an aspect of i the invention there isa'ccordingly provided in combination (a) aphot'o' graphic element-- comprising a photographic silver salt layer,..,(b) a.viscous ,processing composition, within, a. releasing means, e.g., a rupturable container, comprising:

(i) a silver halide solvent, (ii)- analkaline development activator,

diaminophenol developing agent or other auxiliary dedeveloping agent describedherein, and (iv) the novel developing agent of this invention, and

Processing conditions, time of development, and the like can vary depending on the desired image, the particular components of the described element, processing composition an'd image receiver. Typically processing is carried out under normal atmospheric conditions and is completed within about seconds, and preferably, within about 10' seconds.

Usually the silver halide solvent will be sodium thiosulfate; however, various organic silver halide complexing agents such as those described by Haist et al., Phot. Sci. Eng, 5, 198 (1961) and in Kodak French Pat. 1,312,687 issued Nov. 12, 1962, and Belgian Pat. 606,559 of Ulrich et al., issued July 26, 1960, and similar agents can also be used.

The light-sensitive element, receiving element or processing composition can also contain toning agents such as, for example, polyvalent inorganic salts of the type described in US. Pat. 2,698,236 of Land issued Dec. 28, 1954, silica as described in U.S. Pat. 2,698,237 of Land issued Dec. 28, 1954, and heterocyclic mercaptans such as the mercapto azoles, e.g., mercapto diazoles, mercapto triazoles and mercapto tetrazoles.

Typically, the developing agent is provided in a viscous liquid photographic developer composition comprising (a) a silver halide solvent, and (b) the silver halide developing agent of the invention. The viscous liquid photographic developer composition can also, contain additional silver halide developing agents,'as described herebaths .are described, for example, in the Monobath Manual, by Grant M. Haist (1966), Morgan and Morgan, Inc., Hastings On Hudson, NY.

Typically, a suitable developer composition according to the invention can comprise a viscous developer containing:

(a) a silver halide solvent, such as sodium thiosulfate, (b) a diaminophenol auxiliary developing agent, such as "6-methoxy-2,4-diaminophenol or 6-ethyl-2,4-diamino- (c) an image receiving layer comprisingdevelopment H nuclei, especially palladium development nuclei, dispersed in a polymeric binder.

Albeit the developing agent is generally located in a releasing means, it can be suitably employed in a variety of locations with regard to a diffusion transfer system. The novel developer can be provided in the silver salt layer or emulsion, in a layer near to the silver salt layer, in the image receiving layer containing silver precipitating nuclei or development nuclei as well as in the rupturable container. I

In accordance with a typical diffusion transfer process a photographic element is exposed imagewise, the exposed silver halide is developed at a pH above 8', typically above 10 and preferably at a pH of about 12 to about 14-, in the presence of the novel developer. The unexposed silver salts in the photosensitive silver salt layer is contacted with a silver halide solvent to form an imagewise distribution of a silver complex in the unexposed areas of said photographic silver salt layer; and at least part of the silver complex is transferred to an imagereceiverglayer containing development nuclei, contiguous to the photo-' sensitive layer, thereby forming' a visible image on saidreceiver layer.

phenol or a 3-pyrazolidone auxiliary developing agent such as l-phenyl-3-pyrazolidone or 1-phenyl-4,4-dimethyl-'3-pyrazolidone, (c) the developing agent of the invention, (d) an alkaline development activator, and

(iii) optionally a py done developing agent a: (e) a thickening agent, such as a cellulose derivative, e.g.,

hydroxyethyl cellulose and/or carboxymethyl cellulose.v

Suitable viscosities for the viscous composition can vary over a wide range. The viscosity is usually from about 20 to about 1000 cps. Various thickening agents are suitably employed in the described processing compositions and processes of the invention. Any of those commonly employed in difiusion transfer photographic systems can be employed. These include those described in the art,

such as cellulose derivatives, e.g., hydroxyethyl cellulose and/ or carboxymethyl cellulose.

In another aspect of this invention, it has been discovered that the developing agents described herein can be utilized in the photographic process generally referred to as dry photography. The elements employed in dry photography are photosensitive, i.e., a latent image is formed imagewise in the exposed areas of a silver salt layer, and thermosensitive, i.e., substantially permanent, visible images of photographic sharpness and high visual contrast can be produced often within seconds through the mere application of heat. The dry photographic ele-. ments are developed by heating to Within a temperature range of from about C. to about 250 C.

I Typically a dry photographic element comprises a support having thereon an oxidation-reduction image forming combination said combination comprising a silver salt, preferably an organic silver salt, and a reducing agent, and a catalyst for the oxidation-reduction image forming combination.

In accordance with an aspect of the invention, the amidoximes either as the developing agent or in combination with an auxiliary developing agent such as a pyrazolidone can be employed as the reducing agent or composition in the dry photographic element.

Other reducing agents as described herein can be employed in combination with the developing agents of this invention, and include, for example, the prior art silver halide developing agents and/or substituted phenols and napthols described in De Mauriac, Belgian Pat. 766,589 issued June 15, 1971.

As the oxidizing agent, of the oxidizing-reduction image forming combination, a silver salt of an organic acid is preferably employed. The silver salt of the organic acid should be resistant to darkening under illumination to prevent undesired deterioration of a developed image. An especially suitable class of silver salts of organic acids is the water insoluble silver salts of long-chain fatty acids which are stable to light. Typically, the silver salts include silver behenate, silver stearate, silver oleate, silver lauratc, silver hydroxystearate, silver caprate, silver myristate, and silver palmitate. Other suitable oxidizing agents are silver benzoate, silver phthalazinone, silver benzotriazole, silver saccharin, silver 4'-n-octadecyloxy-diphenyl-4 carboxylic acid, silver orthoamino-benzoate, silver acetamidobenzoate, silver furoate, silver comphorate, silver p-phenylbenzoate, silver phenyl acetate, silver salicylate, silver butyrate, silver terephthalate, silver phthalate, silver acetate, and silver acid phthalate. Nonsilver salts can be employed as oxidizing agents, such as zinc oxide, gold stearate, mercuric behenate, auric behenate and the like, however, silver salts are generally preferred.

Typically, a photosensitive salt is present in the dry photographic elements in minor or catalytic amounts. A suitable concentration range of the catalyst is generally from about 0.01 to about 0.50 mole of photosensitive silver salt per mole of oxidizing agent. Suitable silver salts include photosensitive silver halides, e.g., silver chloride, silver bromide, silver bromoiodide, silver chlorobromoiodide, or mixtures thereof. I

The dry photographic elements preferably contain an activator-toning agent. Suitable activator-toning agents which can be employed include cyclic imides such as:

Phthalimide, N-hydroxyphthalimide, N-potassium phthalimide, N-mercury phthalimide, Succinimide, and N-hydroxysuccinimide.

Other activator-toning agents can be employed in combination with or in place or the cyclic imides. Such other activator-toning agents are generally heterocyclic compounds containing at least two hetero atoms in the heterocyclic ring, at least one being nitrogen. Illustrative compounds include phthalazinone, phthalic anhydr'ide, 2-acetylphthalazinone and 2-phthalylphthalazinone. Grant US. Pat. 3,080,254 issued Mar. 5, 1963, and Workman US. Pat. 3,446,648 issued May 27, 1969, describe suitable activator-toning agents.

Activator-toning agents are suitably employed at a concentration of about 0.10 mole to about 1.05 moles per mole of oxidizing agent, however, lower and higher concentrations can be employed.

The following examples are included for a further understanding of the invention.

EXAMPLE 1 Preparation of compounds 8 equivalent of sodium methoxide in methanol, keeping the temperature below 15 C. Sodium chloride is filtered off and washed with a small amount of methanol. The corresponding nitrile is added to the filtrate. This reaction mixture is kept at room temperature for 1-2 days. It is then concentrated, and the precipitated amidoxime filtered off and recrystallized.

The-preparation of formamidoxime is taken from J. Barrows,Chemical Abstracts, 60: 12004 (1964).

' I Use in dry physical development systems A mixture of silver behenate and behenic acid as described in U.S. Pat. 3,457,075 of Morgan et al. issued July 22, 1969, is prepared by precipitation with silver nitrate from a solution of sodium behenate and behenic acid in non-polar solvent. The precipitate is thoroughly washed and dried. I j v I A coating composition is prepared by mixing the following components:

Silver behenate g 42.0 Behenic acid g 32.0 Polyvinyl butyral ..-g 15.0 Acetone-toluene (1:1 parts by volume) ml 500 After ball-millingfor about 18 hours, 75.0 ml. of an acetone solution containing 1 percent by Weight of lithium bromide is added to the above dispersion and the mixture is stirred situ. The resulting dispersion is coated on a paper support at a wet thickness of 0.006 in. The resulting coating is dried. y

Various amidoximes as described in Table I are dissolved in an acetone methyl alcohol solution to provide a 0.02 molar concentration. The solution is then spotted on to" the described photosensitive element with a glass stirringrod and dried. No activator-toning agent is added to the composition. The coating is dried and then exposed imagewise to light. The element is then heated on a mandrel to C. As will be seen in Table I, strong images are obtained in times of from 2 to 10 seconds. The images are generally black in hue and nov auxiliary toning or accelerating agent is necessary. In contrast, hydroxylaminesulfate, an agent of the priorv art, produces almost no imageunder these test conditions.

. 1 EXAMPLE 3 i j Dry physical developmentin presence of toning agent V A coating similar to that of Example 2 is employed except that the coating alsocontains phthalazinone, the chemical commonly employed in the art as a toner-ac- TABLE II.DEVELOPMENT WITH PHTHALAZINONE 115 0.

Density of- Time,

(sec.) Image Compound No. Image tone 15 Orange.

6 .--do None Neutral.

15 Fair.. ...do.. 0.

12 Good (10-- Do.

15 Fair -do- Warm black 15 -..do.. .do. 0.

15 Good ..do......- Neutral.

15 Fair.... do Warm black 15 ...do ..do Neutral.

EXAMPLE 4 Use for aqueous development Various amidoximes, as listed in Table II, are employed in a solution containing 0.02 molar concentrations of the developing agents, 0.2 molar sodium sulfite and 0.5 molar sodium hydroxide.

TABLE IIL-DEVELOPMENT IN AQUEOUS SOLUTION Density oi Compound Time, No. min. Image Fog A fine grain bromoiodide emulsion is exposed to a step wedge and developed in each solution for a series of times at 68 F. Although the compounds do not develop rapidly,

images of good density and low fog are produced on prolonged developmenh 'lhis test is repeated, except the solution is modified by the addition of .002 molar 1-phenyl-3- pyrazolidone. The activity of the developer is very greatly increased as is shown in Table'IV. This"'illust'rates that the amidoximes of our invention can be advantageously combined with other developers. In this case strong superaddi tive development is obtained.

TABLE IV.--MIXTURES WITH 1-PHENYL-3-PYRAZOLIDONE Density of-- Compound Time, a e No. min. Image Fog EXAMPLE 5 Freedom from staining propensity Low-refiectance ldensity under 0.3 Fair-reflectance density 0.3-0.8 Good-reflectance density over 0.8.

invention-has been described particular reference to preferred embodiments thereof. It will be under- 10 stood .that variations and modifications can be effected within the spirit and scope of the invention.

We claim:

1. A; photographic processing composition comprising an alkaline-development activator, and an amidoxime silver salt developing agent, wherein said amidoxime is represented by the structural formula:

RCII=NOH NHQ wherein R is H, a heterocyclic group having 5 or 6 atoms,

CHnN(CH7F-NHOH) 2. A photographic composition of claim 1 which also contains a silver halide solvent.

3. A photographic processing composition of claim 1 which also contains a pyrazolidone auxiliary silver halide developing agent.

4. A photographic composition of claim 3 wherein the mole ratio of the amidoxime to pyrazolidone is in the range of from about 20:1 to about 5:1.

5. A photographic element comprising a support having thereon at-least one photographic silver halide layer and incorporated in said element as a silver halide developing agent, an amidoxime represented by the structural formula:

wherein R is H, a heterocyclic group having 5 or 6 atoms,

.6. A photographic element of claim 5 which also includes a pyrazolidone developing agent.

7. A photographic element of claim 5 wherein said developing agent is present in said silver halide emulsion layer.

.8. A photographic element as in claim 5 wherein said developing-agent is in a layer contiguous to said silver halide layer.

9. A photographic element as in claim 5 wherein said amidoxime is located in said silver halide emulsion layer and a pyrazolidone developing agent is in a layer contiguous to said silver halide layer.

10. A process of developing an exposed photographic element, said element comprising a support having thereon at least one photographic silver halide layer, said process comprising contacting said exposed element with an amidoxime developing agent represented by the structural formula:

RC=N-OH wherein R is H, a heterocyclic group having 5 or 6 atoms,

11 g 12 CH3, z s a 'z C1CH2, z 4 C6H5,: P- s 4 I References cited I 1 P'HOC6H4 P'HQOC"CGH? UNITED STATES PATENTS f H -fg g g gfi fgg 2 336 598 12/1943 Y Dov vning 61 61 96-66 I 2,675,314 4/1954 -;Vittum et a1. 96-109 R C m SfC2H4 C(:NH)NHOH 5 2,758,028 8/1956 Levy et a1. 1 96-1141 2 FCGH C(,=NH)NHOH 2,739,893; 3/1956r1Levy 96-114.6 P C H O 4C H C( NH)NI- IOH of 2,756,146 7/1 Levy 96 -114.5 5 4 6 2,835,577 5/1958 Levy 9 -114.,6

CH CHC-NHOH 1 OTHER REFERENCES Mason: Photographic Processing Chemistry, 1966, pp. -11. A process of developing an exposed photographic 155457 170473- 1 element of claim 5 wherein the amidoxime developin 3 agent is activated by heating the photographic element. g 15 NORMAN G"TORCHIN"Pl-H.I 1ary Exammer 12. A process of developing an exposed photographic M. F. KELLEY, Assistant Examiner element of claim 5 wherein the amidoxime developing V agent is activated by contacting said element with an lk lin iva r. 9648 PD, UX, 66 R, 66 T, 76 XR, 95, 114.1 UX 

